1. Field of the Invention
This invention in general relates to apparatus for testing sonar systems, and more particularly to sonar systems having beamformer circuitry for forming one or more high resolution receiver beams.
2. Background Information
Various types of sonar systems such as sector scan and side-looking sonars utilize electronic beamformer circuitry to form one or more very narrow high resolution beams for acoustically examining a target area. The sonar system must be tested periodically to ensure that it is in proper operating condition and for this purpose many systems include built in test equipment (BITE). By operator switch selection of BITE, a test signal is introduced into the sonar receiver front end which produces a test pattern on a display. Although this technique is less time consuming and less costly than bench testing or test range measurement, current BITE systems are inadequate for locating faults which degrade beam pattern shapes. Only a qualitative result is obtained in that a BITE signal injected into the front end of the sonar receiver will show up on the display thereby informing the operator that there is a signal route through. Current BITE arrangements will not indicate in a quantitative manner the degree to which something is wrong with the sonar receiver and associated transducer elements. It is the beam pattern shape, including the effects from the transducer elements, which should be used to judge system performance level. The apparatus of the present invention will provide a quantitative indication of malfunction and will do so even during in situ operation of the sonar apparatus.